Techniques for identifying when to change an air filter

• US 20060187070A1
• Filed: 02/07/2005
• Published: 08/24/2006
• Est. Priority Date: 02/07/2005
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Seyed, Saeed, Liang, Hsing-Sheng
• Granted Patent: US 7,253,743 B2
• Time in Patent Office: Days
• US Class Current: 340/607
• CPC Class Codes: B01D 46/0086 Filter condition indicators
• CPC Class Codes: B01D 46/442 by measuring the concentration of particles
• CPC Class Codes: B01D 46/88 Replacing filter elements
• CPC Class Codes: G01F 1/74 Devices for measuring flow of a fluid or flow of a fluent solid material in suspension in another fluid
• CPC Class Codes: G01N 15/06 Investigating concentration of particle suspensions by weighing G01N5/00; investigating sedimentation of particle suspensions G01N15/04; investigating individual particles G01N15/10

Abstract

A method is performed in an electronic system having (i) hardware configured to perform electronic operations and (ii) an air filter configured to remove contamination from an air stream that cools the hardware. The method, which identifies when to change an air filter, involves obtaining, from a set of particle sensors, a set of sensor signals in response to sensed particles in the air stream. The method further involves generating particle count data and processing the data based on the set of sensor signals, and providing an output signal having one of a first value and a second value based on the particle count data. The output signal indicates that the air filter should be changed when the output signal has the first value. The output signal indicates that the air filter should not be changed when the output signal has the second value.

Claims

1. In an electronic system having (i) hardware configured to perform electronic operations and (ii) an air filter configured to remove contamination from an air stream that cools the hardware, a method for identifying when to change the air filter, the method comprising:

obtaining, from a set of particle sensors, a set of sensor signals in response to sensed particles in the air stream;

generating particle count data based on the set of sensor signals; and

providing an output signal having one of a first value and a second value based on the particle count data, the output signal indicating that the air filter should be changed when the output signal has the first value, and the output signal indicating that the air filter should not be changed when the output signal has the second value.

2. The method of claim 1 wherein the air filter has an inlet side and an exhaust side, the air stream flowing toward the inlet side and from the exhaust side;

wherein the set of sensor signals includes an inlet sensor signal and an exhaust sensor signal;

wherein the set of particle sensors includes (i) an inlet-side particle sensor disposed between an external air source and the inlet side of the air filter, the inlet-side particle sensor being configured to provide the inlet sensor signal, and (ii) an exhaust-side particle sensor disposed between the hardware and the exhaust side of the air filter, the exhaust-side particle sensor being configured to provide the exhaust sensor signal; and

wherein generating the particle count data includes;

generating an inlet result based on the inlet sensor signal, the inlet result representing a quantity of particles flowing toward the air filter in a particular unit of time; and

generating an exhaust result based on the exhaust sensor signal, the exhaust result representing a quantity of particles flowing from the air filter in the particular unit of time.

3. The method of claim 2 wherein providing the output signal includes:

producing a difference result which identifies a difference between the inlet result and the exhaust result;

initially providing the second value in the output signal when the difference result is below a predetermined threshold; and

providing the first value in the output signal once the difference result exceeds the predetermined threshold.

4. The method of claim 1 wherein the air filter has an inlet side and an exhaust side, the air stream flowing toward the inlet side and from the exhaust side;

wherein the set of sensor signals includes an exhaust sensor signal;

wherein the set of particle sensors includes an exhaust-side particle sensor disposed between the hardware and the exhaust side of the air filter, the exhaust-side particle sensor being configured to provide the exhaust sensor signal; and

wherein generating the particle count data includes;

initializing contents of a counter and updating the contents of the counter based on the exhaust sensor signal, the contents of the counter representing a quantity of particles within a particular particle size range flowing from the air filter in a particular unit of time.

5. The method of claim 4 wherein providing the output signal includes:

comparing the contents of the counter to a predetermined threshold;

initially providing the second value in the output signal when the contents of the counter do not exceed the predetermined threshold; and

providing the first value in the output signal once the contents of the counter exceed the predetermined threshold.

6. The method of claim 1 wherein the air filter has an inlet side and an exhaust side, the air stream flowing toward the inlet side and from the exhaust side;

wherein the set of sensor signals includes multiple exhaust sensor signals;

wherein the set of particle sensors includes an exhaust-side particle sensor disposed between the hardware and the exhaust side of the air filter, the exhaust-side particle sensor being configured to provide the multiple exhaust sensor signals; and

wherein generating the particle count data includes;

initializing contents of counters and updating the contents of the counters based on the multiple exhaust sensor signals, the contents of the counters representing respective quantities of particles within respective particle size ranges flowing from the air filter in a particular unit of time.

7. The method of claim 6 wherein providing the output signal includes:

forming a particle size distribution profile from the contents of the counters;

comparing the formed particle size distribution profile to a predetermined particle size distribution profile, the predetermined particle size distribution profile corresponding to unacceptable filter performance;

initially providing the second value in the output signal when the formed particle size distribution profile and the predetermined particle size distribution profile do not significantly match; and

providing the first value in the output signal once the formed particle size distribution profile and the predetermined particle size distribution profile significantly match.

8. The method of claim 6 wherein providing the output signal includes:

forming a particle size distribution profile from the contents of the counters;

comparing the formed particle size distribution profile to a predetermined particle size distribution profile, the predetermined particle size distribution profile corresponding to acceptable filter performance;

initially providing the second value in the output signal when the formed particle size distribution profile and the predetermined particle size distribution profile significantly match; and

providing the first value in the output signal once the formed particle size distribution profile and the predetermined particle size distribution profile do not significantly match.

9. The method of claim 1 wherein the hardware is configured to perform data communications operations within a computerized network, and wherein the method further comprises:

running the hardware to perform the data communications operations within the computerized network while concurrently providing the output signal to indicate whether the air filter, which is configured to remove contamination from the air stream that cools the hardware, should be changed.

10. The method of claim 9 wherein the wherein the air filter has an inlet side and an exhaust side, the air stream flowing toward the inlet side and from the exhaust side;

wherein the set of particle sensors includes an exhaust-side particle sensor disposed between the hardware and the exhaust side of the air filter; and

wherein obtaining the set of sensor signals includes;

acquiring multiple exhaust sensor signals from the exhaust particle sensor, each exhaust sensor signal providing a measurement of particles within a respective particle size range flowing from the exhaust side of the air filter toward the hardware configured to perform the data communications operations within the computerized network.

11. An electronic system, comprising:

hardware configured to perform electronic operations;

an air filter configured to remove contamination from an air stream that cools the hardware; and

a controller configured to identify when to change the air filter, the controller including;

a set of particle sensors configured to sense particles in the air stream and provide a set of sensor signals in response to sensed particles in the air stream;

processing circuitry coupled to the set of particle sensors, the processing circuitry being configured to generate particle count data based on the set of sensor signals, and

output circuitry coupled to the processing circuitry, the output circuitry being configured to provide an output signal having one of a first value and a second value based on the particle count data, the output signal indicating that the air filter should be changed when the output signal has the first value, and the output signal indicating that the air filter should not be changed when the output signal has the second value.

12. The electronic system of claim 11 wherein the hardware is configured to perform data communications operations within a computerized network while the controller concurrently provides the output signal to indicate whether the air filter, which is configured to remove contamination from the air stream that cools the hardware, should be changed.

13. The electronic system of claim 12 wherein the air filter has an inlet side and an exhaust side, the air stream flowing toward the inlet side and from the exhaust side;

wherein the set of sensor signals includes an inlet sensor signal and an exhaust sensor signal;

wherein the set of particle sensors includes (i) an inlet-side particle sensor disposed between an external air source and the inlet side of the air filter, the inlet-side particle sensor being configured to provide the inlet sensor signal, and (ii) an exhaust-side particle sensor disposed between the hardware and the exhaust side of the air filter, the exhaust-side particle sensor being configured to provide the exhaust sensor signal;

wherein the processing circuitry, when generating the particle count data, is configured to;

generate an inlet result based on the inlet sensor signal, the inlet result representing a quantity of particles flowing toward the air filter in a particular unit of time; and

generate an exhaust result based on the exhaust sensor signal, the exhaust result representing a quantity of particles flowing from the air filter in the particular unit of time; and

wherein the output circuitry, when providing the output signal, is configured to;

produce a difference result which identifies a difference between the inlet result and the exhaust result, initially provide the second value in the output signal when the difference result is below a predetermined threshold, and

provide the first value in the output signal once the difference result exceeds the predetermined threshold.

14. The electronic system of claim 12 wherein the air filter has an inlet side and an exhaust side, the air stream flowing toward the inlet side and from the exhaust side;

wherein the set of sensor signals includes an exhaust sensor signal;

wherein the set of particle sensors includes an exhaust-side particle sensor disposed between the hardware and the exhaust side of the air filter, the exhaust-side particle sensor being configured to provide the exhaust sensor signal;

wherein the processing circuitry, when generating the particle count data, is configured to;

initialize contents of a counter and update the contents of the counter based on the exhaust sensor signal, the contents of the counter representing a quantity of particles within a particular particle size range flowing from the air filter in a particular unit of time, and

wherein the output circuitry, when providing the output signal, is configured to;

compare the contents of the counter to a predetermined threshold,

initially provide the second value in the output signal when the contents of the counter do not exceed the predetermined threshold, and

provide the first value in the output signal once the contents of the counter exceeds the predetermined threshold.

15. The electronic system of claim 12 wherein the air filter has an inlet side and an exhaust side, the air stream flowing toward the inlet side and from the exhaust side;

wherein the set of sensor signals includes multiple exhaust sensor signals;

wherein the set of particle sensors includes an exhaust-side particle sensor disposed between the hardware and the exhaust side of the air filter, the exhaust-side particle sensor being configured to provide the multiple exhaust sensor signals;

wherein the processing circuitry, when generating the particle count data, is configured to;

initialize contents of counters and update the contents of the counters based on the multiple exhaust sensor signals, the contents of the counters representing respective quantities of particles within respective particle size ranges flowing from the air filter in a particular unit of time; and

wherein the output circuitry, when providing the output signal, is configured to;

form a particle size distribution profile from the contents of the counters,

compare the formed particle size distribution profile to a predetermined particle size distribution profile, the predetermined particle size distribution profile corresponding to unacceptable filter performance,

initially provide the second value in the output signal when the formed particle size distribution profile and the predetermined particle size distribution profile do not significantly match; and

provide the first value in the output signal once the formed particle size distribution profile and the predetermined particle size distribution profile significantly match.

16. The electronic system of claim 12 wherein the air filter has an inlet side and an exhaust side, the air stream flowing toward the inlet side and from the exhaust side;

wherein the set of sensor signals includes multiple exhaust sensor signals;

wherein the set of particle sensors includes an exhaust-side particle sensor disposed between the hardware and the exhaust side of the air filter, the exhaust-side particle sensor being configured to provide the multiple exhaust sensor signals;

wherein the processing circuitry, when generating the particle count data, is configured to;

initialize contents of counters and update the contents of the counters based on the multiple exhaust sensor signals, the contents of the counters representing respective quantities of particles within respective particle size ranges flowing from the air filter in a particular unit of time; and

wherein the output circuitry, when providing the output signal, is configured to;

form a particle size distribution profile from the contents of the counters,

compare the formed particle size distribution profile to a predetermined particle size distribution profile, the predetermined particle size distribution profile corresponding to acceptable filter performance,

initially provide the second value in the output signal when the formed particle size distribution profile and the predetermined particle size distribution profile significantly match, and

provide the first value in the output signal once the formed particle size distribution profile and the predetermined particle size distribution profile do not significantly match.

17. The electronic system of claim 12 wherein the wherein the air filter has an inlet side and an exhaust side, the air stream flowing toward the inlet side and from the exhaust side;

wherein the set of particle sensors includes an exhaust-side particle sensor disposed between the hardware and the exhaust side of the air filter; and

wherein the set of particle sensors, when providing the set of particle sensor signals, is configured to;

output multiple exhaust sensor signals, each exhaust sensor signal providing a measurement of particles within a respective particle size range flowing from the exhaust side of the air filter toward the hardware which is configured to perform the data communications operations within the computerized network.

18. The electronic system of claim 12 wherein a microprocessor concurrently forms (i) at least part of the hardware configured to perform electronic operations, (ii) the processing circuitry configured to generate the particle count data, and (iii) the output circuitry configured to provide the output signal.

19. An electronic system, comprising:

hardware configured to perform electronic operations;

an air filter configured to remove contamination from an air stream that cools the hardware; and

a controller configured to identify when to change the air filter, the controller including;

means for sensing particles in the air stream and providing a set of sensor signals in response to sensed particles in the air stream;

processing circuitry coupled to the means for sensing and providing, the processing circuitry being configured to generate particle count data based on the set of sensor signals, and

output circuitry coupled to the processing circuitry, the output circuitry being configured to provide an output signal having one of a first value and a second value based on the particle count data, the output signal indicating that the air filter should be changed when the output signal has the first value, and the output signal indicating that the air filter should not be changed when the output signal has the second value.

20. The electronic system of claim 19 wherein the hardware is configured to perform data communications operations within a computerized network while the controller concurrently provides the output signal to indicate whether the air filter, which is configured to remove contamination from the air stream that cools the hardware, should be changed.